1. Technical Field
The present invention relates to a light-emitting device and a projector.
2. Related Art
There is known a light-emitting device obtained by forming a light-emitting layer made of a group-III nitride semiconductor on a substrate, injecting a current from an external portion, and combining electrons and holes inside the light-emitting layer so as to emit light. In such a light-emitting device, a strain may be generated between a light-emitting layer and a substrate. Particularly, when InGaN is used in the light-emitting layer and materials other than InGaN (for example, GaN) are used in the substrate, lattice mismatch therebetween is generated and the strain increases. When such the strain is generated, an electric field due to a piezoelectric effect (piezoelectric field) is applied to the light-emitting layer, and a radiative recombination probability between electrons and holes is noticeably reduced.
In order to address the aforementioned problem, for example, there has been proposed a method for relaxing a strain generated between the light-emitting layer and the substrate by forming the group-III nitride semiconductor using a fine columnar crystal structure as disclosed in JP-A-2008-169060.
However, according to the technique disclosed in JP-A-2008-169060, a side surface of a fine columnar crystal structure is exposed. Therefore, non-radiative recombination caused by an impurity or a defect near the side surface occurs, and light-emitting efficiency may be degraded.